Reversible towing winch and method for operating same

ABSTRACT

A hydraulically controlled towing winch comprises two winch clutches adapted to rotate a cable drum in opposite directions by selective disengagement of one of the clutches. A normally disengaged input clutch is adapted to selectively couple a power input shaft to a bevel gear arrangement of the winch mechanism for operation thereof. A single lever control system may be utilized to selectively control the actuation of the input and winch clutches to place the winch in the following modes of operation: &#39;&#39;&#39;&#39;Reel-out&#39;&#39;&#39;&#39; wherein the input clutch is engaged and only one of the winch clutches is disengaged to pay-out the cable by rotating the drum in a first direction; &#39;&#39;&#39;&#39;Reel-in&#39;&#39;&#39;&#39; wherein the input clutch is engaged and only the other one of the winch clutches is disengaged to rotate the cable drum in an opposite direction; and &#39;&#39;&#39;&#39;Free-spool&#39;&#39;&#39;&#39; wherein both of the winch clutches are disengaged to permit the drum to rotate freely.

United States Patent Yates et al.

REVERSIBLE TOWING WINCH AND METHOD FOR OPERATING SAME Inventors: Lyle F.Yates, Metamora; Hugh C. Morris, Peoria; James L. Schmitt, Washington,all of 111.

Assignee: Caterpillar Tractor Co., Peoria, lll.

Filed: June 9, 1971 Appl. No: 151,367

References Cited UNITED STATES PATENTS Primary ExaminerAllan D. HermannAssistant Examiner-Randall Heald A tt0rney-Fryer, Tjensvoid, Feix,Phillips & Lempio [57] ABSTRACT A hydraulically controlled towing winchcomprises two winch clutches adapted to rotate a cable drum in oppositedirections by selective disengagement of one of the clutches. A normallydisengaged input clutch is adapted to selectively couple a power inputshaft to a bevel gear arrangement of the winch mechanism for operationthereof. A single lever control system may be utilized to selectivelycontrol the actuation of the input and winch clutches to place the winchin the following modes of operation: Reel-out wherein the input clutchis engaged and only one of the winch clutches is disengaged to pay-outthe cable by rotating the drum in a first direction; Reel-in" whereinthe input clutch is engaged and only the other one of the winch clutchesis disengaged to rotate the cable drum in an opposite direction; andFree-spool wherein both of the winch clutches are disengaged to permitthe drum to rotate freely.

24 Claims, 6 Drawing Figures Patented A ril 24, 1973 3,729,171

4 Sheets-Sheet 1 H :EJLE 3 1/9 47 [)4 IO 6 :15 i

INVENTORS LYLE F. YATES HUGH C. MORRIS JAMES L. SCHMITT Patented April24, 1973 3,729,171

4 Sheets-Sheet 1 Ef 5 I 263 2% INVENTORS LYLE F. YATES HUGH C. MORRISJAMES L. SCHMITT I BY 7? g A'P'jRNEYS REVERSIBLE TOWING WINCH AND METHODFOR OPERATING SAME BACKGROUND OF THE INVENTION Towing winches are widelyused in the construction, logging, pipeline-laying, mining andreclamation industries. Conventional winches are normally actuated by apower take-off from the engine of a machine on which the winch ismounted. Many such winches are unduly complex, expensive to manufacture,prone to mechanical failure when subjected to severe operatingconditions and do not always exhibit the safety features required bymodern day standards. For example, a typical winch may employ twoclutches and a normally engaged friction type brake operativelyassociated with a cable drum to provide the various operating functions.

SUMMARY AND OBJECTS OF THIS INVENTION An object of this invention is toovercome the above,

1 briefly described problems by providing an efficient BRIEF DESCRIPTIONOF THE DRAWINGS Other objects of this invention will become apparentfrom the following description and accompanying drawings wherein:

FIG. 1 is a side elevational view of a track-type tractor having atowing winch embodiment of this invention mounted thereon;

Shaft 14 has a first bevel gear 15 secured to an end thereof whichmeshes with opposed second and third bevel gears 16 and 17 of the winchinput means (FIG. 4). Bevel gear 16 is secured to a carrier 18,rotatably mounted on a shaft 19. The carrier and shaft are adapted to becoupled together by drive means including a first, normally engagedwinch clutch means 20 comprising sets of interleaved friction discs 21alternately mounted for axial movement on the carrier and shaft bystandard spline connections. The friction discs are disengaged when aclutch chamber 22 is pressurized to move an annular piston assembly 23FIG. 2 schematically illustrates the winch and a hydraulic controlsystem therefor;

FIGS. 3 and 4 are sectional views of portions of the.

drive train employed in the winch;

FIG. 5 is a sectional view of a directional control servo valve of theFIG. 2 control system, shown in a high idle condition of operation; and

FIG. 6 schematically illustrates an alternative embodiment of the winchand control system of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS downwardly in FIG. 4. The discsare normally compressed together to engage the clutch by means ofback-to-back Belleville type spring washers 24.

Bevel gear 17 is adapted to impart drive through a substantiallyidentical second winch clutch means 25 comprising a carrier 26,rotatably mounted on common shaft 19, and interleaved clutch discs 27alternately splined for axial movement on the carrier and shaft.Belleville type spring washers 28 normally engage the clutch whereaspressurization of an actuating chamber 29 will disengage same by movinga piston assembly 30 upwardly in FIG. 4. When both clutches 20 and 25are engaged, the drive train is locked, which prevents a cable drum 47from rotating.

When only second winch clutch 25 is disengaged, bevel gear 16 willrotate carrier 18 and thus shaft 19 in a first rotational direction.Conversely, when only first winch clutch 20 is disengaged, bevel gear 17will impart rotation to carrier 26 to in turn rotate shaft 19 in anopposite direction. Pressurization of both chambers 22 and 29 willpermit shaft 19 to rotate freely during a free spool mode of winchoperation, hereinafter fully described.

Referring to FIG. 2, shaft 19 and a coaxial shaft 31 are mounted forrotation in bearings 32 and connected together by gear reduction meanscomprising a planetary gear set 33. The conventional planetary gear setcomprises a stationary ring gear 34, a sun gear 35, planet gears 36, anda carrier 37 secured to shaft 31. The shaft has a pinion gear 38 securedthereto which meshes with a gear 39, which in turn drives a gear 40secured to a shaft 41, rotatably mounted in the winch.

Gear 40 meshes with a gear 42'secured to a hub 43, splined or otherwisesuitably secured to a shaft 44. The latter shaft is suitably mounted forrotation in spaced stationary bearings 45 and 46 and has a cable drum 47attached thereto. An optional method not shown would be to mount drum 47and gear hub 43 on suitable bearings and support shaft 19 in thestationary housing. The cable drum may have a standard cable 48 (FIG. 1)entrained thereon in a conventional manner to perform the various winchoperations. Cable 48 can be wound on drum 47 to pass rearwardly from thetop or bottom of the drum corresponding to the overwind and underwindconditions shown in FIG. 1.

The FIG. 2 control system comprises a single control lever 50 which maybe selectively moved by the operator in slots 51-54 to condition thecontrol system for the following modes of winch operation: Neutral (N)wherein the lever is positioned in horizontal slot 51 to engage winchclutches 20 and 25 and to disengage power input clutch l1; Reel-out (0)wherein the lever is moved downwardly in slot 52 to disengage one of thewinch clutches only and to engage the input clutch to rotate drum 47 ina first direction to pay-out icable therefrom; Reel-in (I) wherein thelever is clutches are disengaged to permit the drum to rotate freely.

Control lever 50 is connected by linkage means, schematicallyillustrated at 55 and 56, to translate the motion thereof to the spoolsof a pressure control valve 57 and a selector control valve 58,respectively. In particular, horizontal movement of the lever in slot 51of the double U-shaped shift pattern will only actuate selector controlvalve 58 whereas vertical downward movement of the lever in slot 52, 53,or 54 will only function to move the spool of pressure control valve 57rightwardly. The lever is springbiased (not shown) to automaticallyreturn it to its FIG. 2 position upon release thereof by the operator.

The integrated control system and functions thereof are-best explainedby describing the above-mentioned modes of winch operation. During allsuch modes of operation, a pressurized fluid source, comprising a sump60 (e.g., the closed chamber of the winch housing which is partiallyfilled with oil), engine driven and positive displacement pump 61 andfilter 62, function to communicate pressurized oil to a conduit 63. Theconduit communicates with an inlet 64 of a directional control servovalve 65 comprising a spool 66 normally biased upwardly by a coil spring67 against a stop member 68. During the Neutral (N) mode'of winchoperation wherein lever 50 is positioned in slot 51, both winch clutchesare drained and engaged to equally share the load for braking cable drum47.

FIG. 2 discloses the control system in a neutral-low engine speed (e.g.,approximately one-half to one-third rated engine speed).condition ofoperation wherein the pumped oil is communicated to a chamber 69. Oil iscommunicated from chamber 69 through orifices 70 and 129 to an outletconduit 71. Pressure is also communicated through a restricted passage72 to a spring chamber 73. As will be hereinafter more fully explained,the level of oil pressure in chambers 69 and 73 is different by anamount equal to the pressure required to force the oil through orifices70 and 129, and passage 72. Thus, it can be seen that if the flow is low(e.g., low engine speed), the force of spring 67 is greater than thepressure difference force and the valve is positioned in the upwardposition as shown. When the flow increases (e.g., higher engine speed),the pressure difference force is greater than the spring force and spool66 moves to the downward position. Because of this feature, spool 66 issaid to be an engine speed sensing device.

Conduit 71 communicates oil to an inlet 74 ofa pressure modulating valve75. The valve comprises a spool 76 biased leftwardly by a coil spring 77and adapted to be moved rightwardly by servo-means including a cupshapedload piston 78.

In the neutral condition shown, pressurized oil from inlet 74communicates with a passage 79 and a lube passage 80. The lube passagein turn communicates low-pressure oil (e.g., 40 psi) to a lube system orlubrication means 81. A relief valve 82 functions to maintain the lubepressure at an acceptable, safe level. The lube system functions to cooland lubricate the friction discs of the winch and input clutch and toalso lubricate the various bearings and gears during all modes of winchoperation.

Valves 57 and are identical valves connected in series, except thatvalve 57 operates by a mechanical means 55 whereas valve 75 moves fromhydraulic pressure flowing through a circuit 94 to piston 78 to providea force on springs 104. Valves 57 and 75 are in series because whenvalve 75 exhausts, it provides the supply to valve 57.

The first movement of means 55 rightwardly moves pressure control valve57 comprising a spool 83 rightwardly to compress a spring 97, whichcloses off to a drain 59 and opens a conduit 94 to supply. Then aspressure builds up in conduit 94, it will reach a level determined bythe load of spring 152. When pressure reaches this level, it exhausts toa lube circuit described before, through spool 83 having a land 84formed thereon which cooperates with an inlet 85 to lube passage 80 toform a variable passage thereat. The size of such passage may becontrolled to induce the desired pressure drop thereacross tocommunicate the lower or downstream pressure, to the lube system. It canbe seen that pressure in circuit 94 can be controlled by the operator byvarying loads on spring 152. Spring 150 serves only to'provide operatorfeel.

When the engine is at low idle and lever 50 is moved leftwardly overslot 52 and toward its 0 position, a spool of selector valve 58 is movedleftwardly by linkage means 56 to its 0 position to condition the systemfor the Reel-out" mode of winch operation. The valve spool is held insuch position by means of a spring loaded detent 91 which engages one ofthree notches 92. Downward movement of the lever to a first position(e.g., twenty percent of the length of slot 52) will function to engageinput clutch 11 under full system pressure (e.g., 250 psi) and to retainsuch pressure throughout full movement of the control lever to its 0position at the bottom of slot 52.

Disengagement of first win'ch clutch 20 is initiated under a lowerpressure (e.g., 60 psi) at the above, first position of lever 50. Theoil pressure communicated to the first winch clutch preferably increasesin direct linear proportion to further downward movement of the controllever. When the lever is in its 0 position at the bottom slot 52, theoil pressure in chamber 22 of the first winch clutch will be at themaximum 250 psi level.

In particular, handle 50 simultaneously moves spool 83 of pressurecontrol valve 57 rightwardly by linkage means 55 to communicate passage79 with an outlet conduit 94 via a controlled, variable passage meanscomprising an annular groove 95 and an annular land 96. The size of thevariable passage means may be controlled by manipulating lever 50 inslot 52, 53, or 54 to effect the desired pressure drop thereacross.Spool 83 is biased leftwardly by a coil spring 97 and by oilcommunicated to a chamber 98, having a positioning slug 99 mountedtherein, by means of a passage 100.

The downstream oil in conduit 94 passes through a restricted orifice 101and into a chamber 102 under the control of a check valve 103. The fluidpressure in chamber 102 initially tends to move load piston 78rightwardly against the inner one of coil springs 104 to open a passagemeans comprising an annular groove 105 and a land 106 of spool 76. Forexample, only a low pressure in chamber 102 is required to move spool 76towards its input clutch fill position.

Upon opening of the valve, oil is communicated to a passage 107 which inturn communicates with a chamber 108 having a reciprocable slug 109positioned therein. Thus, the oil pressure in chamber 102, tending tomove spool 76 rightwardly, is counteracted by means of springs 77 and104 and the fluid pressure in chamber 108 to provide means for graduallyfilling the actuating chamber of the input clutch to prevent abruptengagement thereof.

Pressurized oil (e.g., 250 psi) is further communicated to a conduit110, an annular groove 111 of directional control servo valve 65 and anoutlet conduit 112. Since spool 90 has been moved leftwardly, a land 113thereof is positioned to communicate conduit 112 with a conduit 114 toin turn communicate pressurized oil to an actuating chamber 115 of inputclutch 11 (FIGS. 2 and 3).

The input clutch further comprises an annular piston assembly 116,biased leftwardly in FIG. 3 by coil springs 117 to normally disengagefriction discs 118 and 119. The discs are splined for axial movement oninput shaft and ring gear 12, respectively. Conversely, pressurizationof chamber 115 compresses the clutch discs together to couple inputshaft 10 to winch input shaft 14 and bevel gear 15.

As shown in FIG. 2, conduit 94 further communicates with a branchconduit 120, annular grooves 121 and 122 of valve 65 and an outletconduit 123. Since spool 90 of valve 58 has been moved to its leftward 0position, a land 124 is also moved leftwardly to block an annular groove125 and to permit conduit 123 to communicate with a groove 126 and aconduit 127. The latter conduit communicates pressurized oil (e.g., 60psi to 250 psi) to chamber 22 of first winch clutch 20 to permit it toslip or to completely release same. When lever 50 is at its 0 positionto only engage the input clutch and the second winch clutch, cable drum47 will be rotated in a first direction to pay-out cable therefrom orReel-out.

Inching control of the cable drum is achieved during low idle bysuitably manipulating lever in slot 52. In particular, such manipulationwill reciprocate valve spool 83 of pressure control valve 57 to provideinching control means for precisely controlling the pressure drop acrossthe variable orifice comprising groove 95 and land 96. The controlledpressure in conduit 94 (e.g., 60 psi to 250 psi) will thus becommunicated to chamber 22 of the first winch clutch to controldisengagement and slippage thereof.

When the engine speed is at high idle (rated speed or above) and lever50 is moved to its 0 position, inching of the winch is preventedautomatically by servo-means to prevent burn-out of the clutch discs.During high idle" the increased oil pressure in chamber 69 of blockingvalve 65 will exceed a predetermined level (e.g., 350 psi). In responsethereto, spool 66 moves downwardly to automatically and constantlycommunicate full system pressure (250 psi) to chambers 115 and 22 of theinput clutch and first winch clutch, respectively.

In particular, substantially full system pressure is communicated fromconduit 110 to both outlet conduits 112 and 123 due to the movement of ablocking land 128 of spool 66 below conduit 123, as shown in FIG. 5.Therefore, the input and winch clutches can only be actuated to an on"or off condition of winch operation and are insensitive to manipulationof spool 83 by lever 50 for winch clutch slippage and inching purposes.The above explained inching-atlow-idle and non-inching-at-high-idleconditions of winch operation will also prevail when lever 50 is movedvertically in slot 53 or 54.

It should be further noted in FIG. 5 that an orifice 129 closes duringthe high idle condition of engine operation to increase the pressuredrop across orifices 70. The upstream pressure in chamber 69 iscontinuously maintained at a sufficiently high level to overcome thecombined force of the downstream pressure in chamber 73 plus the forceof spring 67. Conversely, during low idle spool 66 will be continuouslyraised to its FIG. 2 position by spring 67 due to the combined outflowof fluid through orifices and 129 which effects a lower pressure dropthereacross.

When lever 50 is moved to its Reel-in" or I position at the bottom ofslot 53, valves 57, 65 and 75 will function substantially asabove-described. However, selector control valve 58 is actuated to movespool thereof rightwardly to its 1 position to block annular groove 126.Therefore, inlet conduit 123 from valve 65 communicates with annulargroove 125 and thus conduit to communicate pressurized fluid to clutchchamber 29 to release second winch clutch 25. Therefore, theabove-described Reel-out mode of operation is reversed and the cabledrum 47 will rotate in an opposite direction to Reel-in.

When lever 50 is moved downwardly in slot 54 to the Free-spool" (F)position, valves 57,65 and 75 will function substantially as abovedescribed. However, spool 90 of selector control valve 58 is nowpositioned at its intermediate F position whereby land 124 will assumethe position illustrated in FIG. 2. Thus, pressurized fluid from conduit123 will communicate to both outlet conduits 127 and 130 to fully orpartially (slip) disengage both of the winch clutches.

In addition, land 113 will be in a blocking position preventing conduit112 from communicating with conduit 114 to thus prevent engagement ofinput clutch 1 1. The winch is now in its Free spool condition ofoperation. As suggested above, the control system could be designed toengage the input clutch during the free-spool mode of operation whereinthe winch clutches are disengaged.

FIG. 6 illustrates an alternative embodiment of the winch and controlsystem of this invention. The winch is driven by a power input means orshaft 210 comprising a standard power take-off from an internalcombustion engine (not shown). A normally disengaged input clutch means211 may be actuated to selectively rotate a bevel gear 215.- The bevelgear in turn meshes with opposed bevel gears 216 and 217, each rotatablymounted on a shaft 219 by conventional bearing means.

The shaft .is rotatably mounted in the winch by spaced bearings 232 andis adapted to drive a pinion gear 238 and speed reduction gears 239,240, and 242. Gear 242 in turn drives a cable drum 247, mounted forrotation on spaced bearing means 245 and 246. A lube system281,corresponding to lube system 81, and a relief valve 282 are employedin the system. The relief valve functions to maintain the systems oilpressure at a maximum level of 40 psi, for example.

The last two numerals included in the above 200 series of numbersbetween 200 and 249 are common to numerals in FIGS. 1-5 which depictcorresponding structures. The FIG. 6 embodiment essentially differs fromthe FIGS. 1-5 embodiment in that the winch clutches are normallydisengaged and three control levers are employed along with an addedbrake 272.

The three levers 250, 251 and 252 are reciprocally mounted in verticallydisposed slots 253, 254 and 255,

respectively. Lever 252 is operatively connected by linkage means 256 toaxially engageable clutch means 257'and 258. Although the clutches couldbe of the above-described frictional disc type (such as shown at 20 and25 in FIG. 4), each clutch preferably comprises an axially movabletoothed collar member attached to the linkage means. The teeth of suchmember interlock with teeth of a second clutch member for positiveengagement therewith to mechanically couple bevel gear 216 or 217 toshaft 219 in a conventional manner.

In the illustrated neutral N position of lever 252, both of the clutchesare disengaged. Downward movement of lever 252 to its 1 position willfunction to engage clutch 257 only to condition the winch for itsReel-in mode of operation. Conversely, movement of lever 252 upwardly toits position will only engage clutch 258 to condition the winch for aReel-out mode of operation.

Downward movement of lever 251 to its ON position will function, viasuitable linkage means, to move a spool 259 of a directional controlvalve 260 rightwardly. An engine driven pump 261 communicatespressurized fluid, preferably oil, through a filter 262 and a conduit263 which terminates at an inlet 264 of valve 260. Since spool 259 hasmoved rightwardly, an annular groove 265 is uncovered to communicateinlet 264 with an outlet conduit 266 to pressurize an actuating chamber211 to engage normally disengaged input clutch 21.1.

Handle 250, when moved downwardly in slot 253 to its OFF position, movesa spool 267, via suitable linkage means, of a pressure control valve 268'rightwardly to communicate pressurized fluid from inlet 264 to anannular outlet groove 269. Pressurized fluid from outlet 269 iscommunicated to a conduit 270 which in turn communicates withanactuating chamber 271 of a normally engaged brake assembly 272 todisengage same. The standard brake assembly may be of the frictionaldisc and slipping type comprising axially movable but non-rotatablebrake discs 273 and axially movable brake discs 274 splined to shaft219. A spring means (schematically shown) normally engages the brake andwill be released by an annular piston 275 which is selectively moved bypressurized oil communicated to actuating chamber 271.

The FIG. 6 winch may be conditioned for the following modes ofoperation: Neutral" wherein levers 250, 251, and 252 are in thepositions illustrated in FIG. 6 to disengage input clutch 211 and thewinch clutches 257 and 258 and to engage brake 272; Reel-Out whereinlever 252 is moved to its 0 position to engage winch clutch 258 only,lever 251 is moved to its ON position to engage input clutch 211, andlever 250 is moved to its OFF position to release brake 272; Reel-In"which is identical to the Reel-Out sequence except that lever 252 ismoved to its 1 position to engage winch clutch 257 only; and Free-Spool"wherein levers 251 and 252 remain in their illustrated position andlever 250 is moved to its OFF position to release brake 272.

It should be noted that inching of the cable drum may be achieved duringthe Reel-Out, Reel-In and Free-Spoolmodes of winch operation bymanipulating lever 250 in slot 253. Such manipulation will control thesize of the variable passage means, comprising groove 269 and a land276, to effect the desired pressure drop thereacross. In responsethereto, brake 272 will slip a desired amount to effect the inchingfunction.

What is claimed is:

1. A winch and control system therefor comprising a power input means,

winch input means,

a normally disengaged input clutch means adapted to be actuated tocouple said power input means to said winch input means,

a cable drum rotatably mounted in said winch;

drive means for operatively connecting said winch input means to saidcable drum to rotate said drum, including first and second winch clutchmeans, and

control means, including a single control lever for effecting selectiveactuation of all of said input and winch clutch means, forsimultaneously engaging said input clutch means and for only disengagingsaid first winch clutch means to rotate said cable drum in a firstdirection; or for simultaneously engaging said input clutch means andfor only disengaging said second winch clutch means to rotate said cabledrum in a second direction opposite to said first direction; or forsimultaneously disengaging said first and second winch clutch means.

2. The invention of claim 1 wherein each of said clutch means is of thefluid actuated, friction disc type and said winch clutch means are eachnormally engaged to constitute the sole means for braking said cabledrum and are selectively disengaged under fluid pressure by said controlmeans.

3. The invention of claim 1 further comprising normally engaged brakemeans for selectively preventing rotation of said cable drum and whereinsaid winch clutch means are each normally disengaged and are alternatelyengaged by said control means.

4. The invention of claim 3 wherein said control means comprises threeseparate control levers for respectively effecting actuation of saidinput clutch means, said first and second winch clutch means and saidbrake means.

5. The invention of claim 1 wherein said winch input means comprises afirst rotatably mounted bevel gear and second and third opposed bevelgears each meshing with said first bevel gear.

6. The invention of claim 5 wherein said second and third bevel gearsare rotatably mounted on a common shaft and wherein said first andsecond winch clutch means normally couple said second and third bevelgears, respectively, to said shaft.

7. The invention of claim 6 wherein said drive means further comprises agear reduction means operatively connecting said shaft to said cabledrum.

8. The invention of claim 2 wherein said control means comprises inchingcontrol means for selectively controlling partial engagement andslippage of at least one of said disengaged clutch means.

9. The invention of claim 8 wherein said control means further comprisesservo-means responsive to the speed of said power input means forautomatically preventing slippage of said disengaged clutch means whensaid speed exceeds a predetermined amount.

10. The invention of claim 9 wherein said servomeans comprises adirectional control servo-valve.

11. The invention of claim 8 wherein said inching control meanscomprises a manually controlled pressure control valve means.

12. The invention of claim 11 wherein said control means furthercomprises a selector control valve means and a single lever operativelyconnected to said selector control valve means and said pressure controlvalve means to effect simultaneous actuation thereof.

13, The invention of claim 11 further comprising lubrication means forcommunicating fluid to each of said clutch means and wherein thepressure level of the fluid communicated to said lubrication means iscontrolled by said pressure control valve means.

14. The invention of claim 2 wherein said control means furthercomprises a directional control valve and servo-means for automaticallycontrolling the pressure rise in an actuating chamber of said inputclutch means.

15. In a winch and control system therefor comprising power input means,a rotatably mounted cable drum operatively connectible to said powerinput means and means for selectively rotating said cable drum,including inching control means for selectively permitting said cabledrum to rotate at a speed independent of the speed of said power inputmeans, the invention comprising servo-means responsive to the speed ofsaid power input means for automatically preventing inching control ofsaid cable drum by said inching control means when the speed of saidinput means exceeds a predetermined amount.

16. The invention of claim 15 wherein said servomeans comprises adirectional control servo-valve.

17. A winch comprising a power input means, including a first bevelgear,

winch input means including second and third opposed bevel gearsrotatably mounted on a common shaft and meshing with said first bevelgear,

a normally disengaged, fluid actuated input clutch means for selectivelycoupling said power input means to said winch input means,

a cable drum rotatably mounted in said winch,

first and second normally engaged, fluid actuated winch clutch meansoperatively connecting said winch input means to said cable drum tonormally prevent rotation thereof and to rotate said cable drum inopposite directions upon alternate disengagement of said first andsecond winch clutch means and control means comprising a single levercontrol for effecting selective actuation of all of said input andclutch means. 18. The invention of claim 17 wherein each of said inputclutch means and said first and second winch clutch means is of theaxially compressed, friction disc yP 19. A method for operating a winch,including a cable drum rotatably mounted therein to be driven by a powerinput means, comprising the steps of actuating a single lever controlfor normally engaging first and second fluid actuated friction discwinch clutches to prevent rotation of said cable drum by said powerinput means and only disengaging said first winch clutch by fluidpressure and rotating said cable drum by said power input means in afirst direction; or

only disengaging said second winch clutch by fluid pressure and rotatingsaid cable drum by said power input means in a second, oppositedirection;

simultaneously disengaging said first and second clutches by fluidpressure to permit said cable drum to rotate freely.

20. The invention of claim 19 further comprising the steps ofsimultaneously engaging a fluid actuated friction disc input clutch whensaid first or second winch clutch is disengaged.

21. The invention of claim 19 further comprising the step of manuallycausing the disengaged winch clutch to at least partially engage andslip.

22. The invention of claim 21 further comprising the step ofautomatically preventing manual, partial engagement of the disengagedwinch clutch when the speed of said power input means exceeds apredetermined amount.

23. A winch and control system therefor comprising a power input means,

winch input means,

a normally disengaged input clutch means adapted to be actuated tocouple said power input means to said winch input means,

a cable drum rotatably mounted in said winch,

drive means for operatively connecting said winch input means to saidcable drum to rotate said drum, including first and second winch clutchmeans,

control means for simultaneously engaging said input clutch means andfor only disengaging said first winch clutch means to rotate said cabledrum in a first direction; or for simultaneously engaging said inputclutch means and for only disengaging said second winch clutch means torotate said cable drum in a second direction opposite to said firstdirection; or for simultaneously disengaging said first and second winchclutch means, and

normally engaged brake means for selectively preventing rotation of saidcable drum and wherein said winch clutch means are each normallydisengaged and are alternately engaged by said control means. I I

24. The invention of claim 23 wherein said control means comprises threeseparate control levers for respectively effecting actuation of saidinput clutch means, said first and second winch clutch means and saidbrake means.

1. A winch and control system therefor comprising a power input means,winch input means, a normally disengaged input clutch means adapted tobe actuated to couple said power input means to said winch input means,a cable drum rotatably mounted in said winch, drive means foroperatively connecting said winch input means to said cable drum torotate said drum, including first and second winch clutch means, andcontrol means, including a single control lever for effecting selectiveactuation of all of said input and winch clutch means, forsimultaneously engaging said input clutch means and for only disengagingsaid first winch clutch means to rotate said cable drum in a firstdirection; or for simultaneously engaging said input clutch means andfor only disengaging said second winch clutch means to rotate said cabledrum in a second direction opposite to said first direction; or forsimultaneously disengaging said first and second winch clutch means. 2.The invention of claim 1 wherein each of said clutch means is of thefluid actuated, friction disc type and said winch clutch means are eachnormally engaged to constitute the sole means for braking said cabledrum and are selectively disengaged under fluid pressure by said controlmeans.
 3. The invention of claim 1 further comprising normally engagedbrake means for selectively preventing rotation of said cable drum andwherein said winch clutch means are each normally disengaged and arealternately engaged by said control means.
 4. The invention of claim 3wherein said control means comprises three separate control levers forrespectively effecting actuation of said input clutch means, said firstand second winch clutch means and said brake means.
 5. The invention ofclaim 1 wherein said winch input means comprises a first rotatablymounted bevel gear and second and third opposed bevel gears each meshingwith said first bevel gear.
 6. The invention of claim 5 wherein saidsecond and thiRd bevel gears are rotatably mounted on a common shaft andwherein said first and second winch clutch means normally couple saidsecond and third bevel gears, respectively, to said shaft.
 7. Theinvention of claim 6 wherein said drive means further comprises a gearreduction means operatively connecting said shaft to said cable drum. 8.The invention of claim 2 wherein said control means comprises inchingcontrol means for selectively controlling partial engagement andslippage of at least one of said disengaged clutch means.
 9. Theinvention of claim 8 wherein said control means further comprisesservo-means responsive to the speed of said power input means forautomatically preventing slippage of said disengaged clutch means whensaid speed exceeds a predetermined amount.
 10. The invention of claim 9wherein said servo-means comprises a directional control servo-valve.11. The invention of claim 8 wherein said inching control meanscomprises a manually controlled pressure control valve means.
 12. Theinvention of claim 11 wherein said control means further comprises aselector control valve means and a single lever operatively connected tosaid selector control valve means and said pressure control valve meansto effect simultaneous actuation thereof.
 13. The invention of claim 11further comprising lubrication means for communicating fluid to each ofsaid clutch means and wherein the pressure level of the fluidcommunicated to said lubrication means is controlled by said pressurecontrol valve means.
 14. The invention of claim 2 wherein said controlmeans further comprises a directional control valve and servo-means forautomatically controlling the pressure rise in an actuating chamber ofsaid input clutch means.
 15. In a winch and control system thereforcomprising power input means, a rotatably mounted cable drum operativelyconnectible to said power input means and means for selectively rotatingsaid cable drum, including inching control means for selectivelypermitting said cable drum to rotate at a speed independent of the speedof said power input means, the invention comprising servo-meansresponsive to the speed of said power input means for automaticallypreventing inching control of said cable drum by said inching controlmeans when the speed of said input means exceeds a predetermined amount.16. The invention of claim 15 wherein said servo-means comprises adirectional control servo-valve.
 17. A winch comprising a power inputmeans, including a first bevel gear, winch input means including secondand third opposed bevel gears rotatably mounted on a common shaft andmeshing with said first bevel gear, a normally disengaged, fluidactuated input clutch means for selectively coupling said power inputmeans to said winch input means, a cable drum rotatably mounted in saidwinch, first and second normally engaged, fluid actuated winch clutchmeans operatively connecting said winch input means to said cable drumto normally prevent rotation thereof and to rotate said cable drum inopposite directions upon alternate disengagement of said first andsecond winch clutch means and control means comprising a single levercontrol for effecting selective actuation of all of said input andclutch means.
 18. The invention of claim 17 wherein each of said inputclutch means and said first and second winch clutch means is of theaxially compressed, friction disc type.
 19. A method for operating awinch, including a cable drum rotatably mounted therein to be driven bya power input means, comprising the steps of actuating a single levercontrol for normally engaging first and second fluid actuated frictiondisc winch clutches to prevent rotation of said cable drum by said powerinput means and only disengaging said first winch clutch by fluidpressure and rotating said cable drum by said power input means in afirst direction; or only disengaging said second winch clutch by fluidpressure and rotating said cable drum by said power input means in asecond, opposite direction; or simultaneously disengaging said first andsecond clutches by fluid pressure to permit said cable drum to rotatefreely.
 20. The invention of claim 19 further comprising the steps ofsimultaneously engaging a fluid actuated friction disc input clutch whensaid first or second winch clutch is disengaged.
 21. The invention ofclaim 19 further comprising the step of manually causing the disengagedwinch clutch to at least partially engage and slip.
 22. The invention ofclaim 21 further comprising the step of automatically preventing manual,partial engagement of the disengaged winch clutch when the speed of saidpower input means exceeds a predetermined amount.
 23. A winch andcontrol system therefor comprising a power input means, winch inputmeans, a normally disengaged input clutch means adapted to be actuatedto couple said power input means to said winch input means, a cable drumrotatably mounted in said winch, drive means for operatively connectingsaid winch input means to said cable drum to rotate said drum, includingfirst and second winch clutch means, control means for simultaneouslyengaging said input clutch means and for only disengaging said firstwinch clutch means to rotate said cable drum in a first direction; orfor simultaneously engaging said input clutch means and for onlydisengaging said second winch clutch means to rotate said cable drum ina second direction opposite to said first direction; or forsimultaneously disengaging said first and second winch clutch means, andnormally engaged brake means for selectively preventing rotation of saidcable drum and wherein said winch clutch means are each normallydisengaged and are alternately engaged by said control means.
 24. Theinvention of claim 23 wherein said control means comprises threeseparate control levers for respectively effecting actuation of saidinput clutch means, said first and second winch clutch means and saidbrake means.